In view of the groundwater quality deterioration， this paper analyzed the data of annual water quality changes at the representative monitoring sites of the Dong-e karst water system， and made contrastive analysis of the water chemistry indicators distribution between in dry season and wet season. The results show that TDS is between 400mg/L and 700 mg/L， change oif total hardness is not obvious， and rainfall recharge is the main factor of leading to the changes of ion content. In 2015， the main type of water is HCO3-Ca in the Dong＇e karst water system， the ions movement rule is basically same in dry season and wet season， and there is water pollution at some monitoring sites， which lead to the change of ion content. TDS concentration in wet season is higher than that in dry season， and TDS concentration in discharge areas， which impactes on the safety of dringking water.